Tunable thermal conductivity in defect engineered nanowires at low temperatures

Abstract

We measure the thermal conductivity ($\ensuremath{\kappa}$) of individual InAs nanowires (NWs), and find that it is three orders of magnitude smaller than the bulk value in the temperature range of 10--50 K. We argue that the low $\ensuremath{\kappa}$ arises from the scattering of phonons in the random superlattice of twin defects oriented perpendicular to the axis of the NW. We observe a significant electronic contribution arising from the surface accumulation layer, which gives rise to the tunability of $\ensuremath{\kappa}$ with the application of an electrostatic gate and a magnetic field. Our devices and measurements of $\ensuremath{\kappa}$ at different carrier concentrations and magnetic field offer a means to study unique aspects of nanoscale thermal transport.